(19)
(11) EP 1 424 435 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
09.06.2004 Bulletin 2004/24

(43) Date of publication A2:
02.06.2004 Bulletin 2004/23

(21) Application number: 03396102.0

(22) Date of filing: 14.11.2003
(51) International Patent Classification (IPC)7: D21C 11/06, D21C 11/12, B01D 3/34, B01D 53/56, B01D 53/58
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR
Designated Extension States:
AL LT LV MK

(30) Priority: 20.11.2002 FI 20022073

(71) Applicant: Andritz Oy
00180 Helsinki (FI)

(72) Inventors:
  • Saviharju, Kari
    02340 Espoo (FI)
  • Eneberg, Henrik
    00680 Helsinki (FI)
  • Jaakkola, Heikki
    00270 Helsinki (FI)
  • Lammentausta, Sakari
    02230 Espoo (FI)
  • Mattelmäki, Esko
    06100 Porvoo (FI)
  • Schönberg, Ake
    10640 Dragsvik (FI)
  • Honkanen, Risto
    02600 Espoo (FI)

(74) Representative: Sorvari, Marjut Riitta Tuulikki 
Andritz Oy Patent Department P.O. Box 500
48601 Kotka
48601 Kotka (FI)

   


(54) Method of reducing nitrogen oxide emissions in a chemical pulp mill


(57) The present invention relates to recovery of ammonia from ammonia-containing material flows in a chemical pulp mill for decreasing nitrogen oxide emissions of the mill. When practicing this method, the ammonia-containing material flow originating from steam stripping of condensates is adjusted by means of alkali to a value of over 10 and is made into contact with steam for separating ammonia from the material flow. The recovered ammonia is used as a chemical in a combustion device in the chemical pulp mill in a way known per se to reduce detrimental nitrogen oxide emissions of the mill.






Search report